PCSO: Pair could face murder charges after 1 in U-Haul dies

Nathan Lamb, left, and Elizabeth Kay are suspected of driving and alter abandoning a U-Haul loaded with suspected undocumented immigrants. One of the immigrants died and the pair could face murder charges. (Source: Pinal County Sheriff's Office)

Some of the occupants were found lying outside the U-Haul. (Source: Pinal County Sheriff's Office)

At least eight of them suffered heat-related conditions. (Source: Pinal County Sheriff's Office)

They were kept in the back end of locked U-Haul during their journey. (Source: Pinal County Sheriff's Office)

FLORENCE, AZ (CBS5) -

A Phoenix man and his girlfriend are facing possible murder charges after one of eight suspected undocumented immigrants found in the back of a U-Haul truck died early Wednesday morning.

Nathan Lamb, who was driving the U-Haul, and Elizabeth Kay, both 25, were arrested and booked into the Pinal County jail on numerous counts of human smuggling, aggravated assault and endangerment, according to a Pinal County Sheriff's Office news release.

Lamb and Kay were bringing a load of the immigrants from Douglas to Phoenix when they stopped and fled, leaving the passengers, according to the release.

Those remaining at the truck were found by deputies and later treated for heat-related illnesses, according to the release.

One of the passengers was placed on life support but later died, and the sheriff's office was preparing to ask the county attorney to charge them with felony murder, according to the release.

An autopsy will determine the exact cause of death, according to the release.

Lamb and Kay said they heard "pounding and banging" from inside the cargo area, but didn't stop right away during a trip from Douglas to Phoenix on Sunday, according to the release.

The pair eventually stopped near Picacho Peak and were alarmed at the condition of the six, became scared and fled, according to the release.

Two of the passengers, one of which later died, were airlifted to the hospital in critical condition, the Pinal County Sheriff's Office said. Six others were taken by ambulance. Two patients were still in the hospital in stable condition Wednesday.

A witness told deputies there were between 14 to 20 undocumented immigrants in the truck when it pulled over at Interstate 10 and Picacho Peak at around 2:10 p.m.

The witness described the group as "falling out and staggering" after the driver and front-seat passenger opened the back end.

Deputies said they learned the group had been picked up in Douglas. The undocumented immigrants said they had paid $5,000 each for the ride to Phoenix. During the journey, many of the occupants became severely dehydrated and overheated due to the extreme heat and bad conditions in the locked vehicle, sheriff's investigators said.

Witnesses said several of the occupants stayed by the vehicle after it parked at the travel center because of dehydration, fatigue and heat stroke.

U.S. Border Patrol agents helped locate all of the people who had fled into the desert.